Elvanol 75-15

Polyvinyl alcohol (PVOH/PVA) is a versatile, water-soluble synthetic polymer widely specified for its strong film-forming capability, high tensile binder strength, and resistance to oils, greases, and organic solvents. The primary performance determinants for PVOH resins are the degree of polymerization (which directly dictates solution viscosity) and the degree of hydrolysis (the mole fraction of residual acetate groups replaced by hydroxyl groups).  To address the processing limits of standard homopolymers—such as gelation under shear or high viscosity at high solids loading—modern formulations incorporate functional copolymer modifications. These modifications optimize dissolution kinetics, suppress foaming, and preserve rheological stability during long-term storage.      1.Comprehensive Elvanol PVA Series Technical Specifications The physical and chemical specifications for the specialized Elvanol series are summarized below: Grade Viscosity (cP, 4% @ 20°C) Hydrolysis (mol%) pH Ash Content (wt%, Na₂O) Key Polymer Characteristic Elvanol 71-30 27.0 – 33.0 99.5 5.0 – 7.0 ≤  0.7% Standard medium viscosity, fully hydrolyzed homopolymer Elvanol 90-50 11.6 – 15.4 99.5 5.0 – 7.0 ≤  0.7% Low viscosity, fully hydrolyzed homopolymer Elvanol T-25 24.0 – 32.0 99.5 5.0 – 7.0 ≤  0.7% Non-foaming, medium-viscosity warp sizing copolymer Elvanol T-66 11.6 – 15.4 99.5 5.0 – 7.0 ≤  0.7% Low viscosity, high-flux recovery warp sizing copolymer Elvanol 80-18 17.0 – 23.0 99.5 5.0 – 7.0 ≤  0.7% Alkaline-soluble, medium viscosity copolymer Elvanol 85-82 25.0 – 32.0 99.5 5.0 – 7.0 ≤  0.7% Rheologically stable, medium viscosity copolymer Elvanol 75-15 11.6 – 15.4 99.5 5.0 – 7.0 ≤  0.7% Medium-low viscosity, high barrier copolymer Note: All listed grades maintain Volatiles < 5.0 wt% and Residual Methanol < 1.0 wt%.   2. Key Industry Application Sectors A. Textile Warp Sizing & Desizing Recovery Systems In high-speed weaving of synthetic and natural spun yarns (such as polyester/cotton blends), maintaining yarn cohesion without causing loom shedding or drop-wire contamination is critical.  Elvanol T-25: Specifically developed for spun yarn warp sizing, this non-foaming copolymer maintains high weaving efficiency even under low-humidity conditions. It allows lower add-on rates when formulated with starch, reducing loom shedding and eliminating the need for enzyme desizing.  Elvanol T-66: Engineered for medium-to-high pressure slashers, T-66 exhibits lower viscosity than T-25. This lower viscosity allows formulations with higher solid concentration, superior yarn splitting in the leasing section, and drastically enhanced membrane flux rates during ultrafiltration PVOH recovery.  Elvanol 80-18: Features accelerated solubility in alkaline wash solutions, enabling easy desizing while minimizing process foam during wet treatment.  B. Paper Sizing, Pigment Binding & Barrier Packaging Surface sizing and metering press applications demand controlled rheology to prevent misting and boundary layer breakdown.  Elvanol 71-30: The industry standard for medium-viscosity fully hydrolyzed PVOH. It delivers greaseproof properties and high oxygen barrier performance, making it widely used in size presses, calender stacks, and boric acid-tackified formulations.  Elvanol 90-50: Designed for high-speed metering size presses operating in excess of 1500 meters per minute. It provides film strength comparable to 71-30 while maintaining a low viscosity profile similar to starches, allowing higher solids formulations.  Elvanol 75-15: Offers high barrier protection against grease and gas transmission in medium-low viscosity coating systems, demonstrating excellent compatibility when co-formulated with starch.  C. Compounded Adhesives & Rheological Stability Concentrated solution storage often leads to structural association of hydroxyl groups, resulting in unwanted viscosity spikes. Elvanol 85-82: A unique medium-viscosity copolymer that resists retrogradation (viscosity increase over time) even at ambient or sub-ambient storage temperatures and higher solids concentration. It provides oil and solvent resistance alongside high bond strength, making it ideal for compounded adhesives, boric acid crosslinked systems, and wood glue formulations.    3. Summary Selection Protocol High Line-Speed Paper Coating (>1500 m/min): Select Elvanol 90-50 (Low viscosity, high solids capability). Ultrafiltration PVOH Recovery in Textiles: Select Elvanol T-66 (High permeate flux, easy desizing).  Cold-Climate/Long-Shelf-Life Adhesives: Select Elvanol 85-82 (Resists viscosity growth at sub-ambient temperatures).  Greaseproof Barrier Packaging with Starch: Select Elvanol 75-15 (High compatibility, medium-low viscosity).     Website: www.elephchem.com whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

1. Mechanism of Elvanol in Paper Surface Treatment In the modern paper industry, surface treatment has become an important means of increasing the added value of paper. Printability, surface strength, and barrier properties against oils and solvents all highly depend on the material selection of the surface sizing or coating system. Elvanol polyvinyl alcohol, as a high-performance water-based film-forming material, is widely used in paper surface treatment.     Elvanol is a fully or highly hydrolyzed polyvinyl alcohol with excellent film-forming ability. Its regular molecular chain structure allows it to form a continuous and dense film during drying, significantly improving the surface strength and barrier properties of the paper. Compared to using starch alone, the film formed by Elvanol is tougher, has stronger chemical resistance to oils, waxes, and solvents, and exhibits higher water resistance.   Using Elvanol in the sizing press or calendering stage can significantly improve the paper's resistance to linting, dusting, and cracking. Even at low addition levels (approximately 10% solids content), it can achieve surface strength and folding strength superior to traditional starch systems. This characteristic makes it particularly suitable for high-filler paper, recycled fiber paper, and paper types requiring high printability.   In addition, Elvanol has good compatibility and can coexist stably with modified starch, CMC, alginates, wax emulsions, and common papermaking additives, providing greater flexibility for papermaking process adjustments.   2. Application Advantages of Elvanol in Improving Barrier, Strength, and Printing Performance ♣ Surface Barrier Properties Elvanol is one of the most powerful water-based barrier film-forming materials in the paper industry. The film it forms has a natural barrier effect against oils, greases, and organic solvents, and is therefore often used in applications such as greaseproof paper, oil-resistant packaging paper, and copier paper. In oil-resistant systems, Elvanol can also serve as an effective carrier for fluorochemicals, improving the stability and efficiency of the overall barrier system.   ♣ Surface Strength and Structural Stability Compared to starch-sized paper, paper treated with Elvanol exhibits superior resistance to surface abrasion, cracking, and linting. Its high bonding strength effectively binds fibers and fine surface particles, reducing linting and dusting, thereby lowering the frequency of blanket contamination and downtime for cleaning during printing. This advantage is particularly evident in high-speed offset printing and high-precision printing. At the same time, Elvanol allows for a higher proportion of fillers or recycled fibers while maintaining strength, helping paper mills control costs while maintaining paper performance.   ♣  Printability and Coating Suitability Elvanol-treated paper surfaces are smoother and have excellent ink holdout. Due to its oil and solvent resistance, ink does not easily penetrate the paper base, resulting in higher print gloss and image clarity. In pigment sizing systems, Elvanol, as a binder, exhibits significantly stronger binding power than acrylic emulsions, styrene-butadiene latex, casein, and starch, and can replace traditional binders at certain ratios, optimizing the pigment/binder ratio.   3. Typical Elvanol Grades and Application Characteristics in Papermaking Based on different paper types and process requirements, we offer a variety of product grades with different viscosities and structures. The following are commonly used grades in the papermaking industry and their application characteristics: Grade Polymer Type Viscosity Level Key Functions Typical Uses Elvanol 71-30 Fully hydrolyzed PVOH Medium Film forming, binding, grease resistance Surface sizing; FWA carrier; lint and dust control; grease-resistant papers Elvanol 80-18 Fully hydrolyzed PVOH Medium Grease barrier, high solids stability Grease-proof packaging papers; high-solids sizing and coating Elvanol 75-15 Fully hydrolyzed PVOH Medium–Low Binder reinforcement Starch reinforcement; lint reduction; high-solids sizing and coating   In optical brightening systems, Elvanol acts as a carrier for fluorescent whitening agents (FWAs), significantly improving whitening efficiency. Adding Elvanol at 0.5–2.5% of the pigment weight in pigment systems results in significantly better whitening effects than using FWA alone, while also reducing the amount of traditional carriers such as starch and casein.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer with excellent film-forming properties, surface activity, and strong adhesion to inorganic and cellulosic materials. Global annual PVA production is approximately 1.05 million tons, with Japan producing approximately 300,000 tons. Approximately 14,100 tons of this is used as a paper processing chemical, a surface sizing agent for plain paper, a sizing agent for coated and coated paper, a fluorescent brightener, an inkjet ink absorber, an adhesive for inorganic fillers, and a silicone sealant for release paper.   The paper business faces challenges like using different types of wood pulp and faster, bigger machines for making paper and printing. Because of this, they need better water-soluble polymers with special features. These polymers are important for making fancy specialty papers and papers used in tech. To adapt to these fundamental changes in the papermaking industry, Kuraray Japan has developed and mastered the properties of modified PVA with novel properties. This article will focus on two specialty PVA: the silanol-modified "R-series PVA" and the high-barrier "Exceval PVA" with the introduction of special hydrophobic groups. The two types will be discussed, along with their properties and applications in paper processing additives.   2. PVA Properties and Dissolution Methods Industrially, PVA is produced by polymerizing and then saponifying polyvinyl acetate. Its fundamental properties depend on its degree of polymerization and saponification. Most commercially available PVAs had a degree of polymerization of 200 to 4000 and a degree of saponification of 30% to 99.9% by mole fraction. The main varieties of PVA produced by Kuraray (Kuraray PVA) are shown in Tables 1 and 2.   3. Specialty Kuraray PVA To date, Kuraray has produced a variety of Kuraray PVAs with varying degrees of polymerization and saponification, which are used in a wide range of applications. As demand grows for better PVA and more varied uses, just tweaking the polymerization and saponification degrees isn't enough anymore. So, Kuraray PVA now comes with special groups added to give it extra function.   This article will introduce two types of functionalized PVA: the "R-series PVA," modified with silanol groups, and the "Exceval PVA (Exceval HR-3010)," which incorporates special hydrophobic groups for high barrier properties.   3.1 Silanol-Modified R-series PVA The R-series is a modified PVA with silanol groups. Table 3 lists the quality standards for the R-series products.     3.2 High Barrier Exceval PVA Exceval PVA is a PVA containing special hydrophobic groups. The introduction of hydrophobic groups enhances the crystallinity of the solid polymer, resolving the dilemma of achieving both high water resistance and stable aqueous solution viscosity, which is difficult to achieve with standard PVA. The use of PVA is increasing annually. PVA is usually used as a stabilizer in adhesives that need to resist water. But, when used in food packaging films, PVA doesn't block oxygen well when it's humid. Exceval PVA is also being developed as an improved material. In coated paper applications, Exceval PVA has also been successfully used when higher water resistance than PVA is required.   This article reports on the results of a new application study for Exceval PVA, specifically its use as an oil-resistant agent in food packaging. The product specifications of the Exceval PVA used in this study are shown in Table 4.   Table 5 shows that coating with Exceval PVA RS-2117 achieves air resistance roughly equivalent to that achieved with partially saponified PVA-217, while significantly reducing water absorption. Paper coated with partially saponified PVA exhibits higher air resistance. This is because the highly hydrophobic, partially saponified PVA has a lower surface tension in aqueous solution, inhibiting penetration into the paper. However, partially saponified PVA suffers from a significant reduction in water resistance. While Exceval PVA, modified with a special hydrophobic group, is fully saponified, it still exhibits the same permeability as partially saponified PVA, offering both improved water resistance and air impermeability.   R-series PVA contains highly reactive silanol groups, which improve adhesion to various inorganic materials. Using the R-series in inkjet media reduces the amount of polyvinyl alcohol used as a binder for silica particles, improving print quality. Even without a crosslinker, the R-series provides high water resistance. Exceval PVA is a modified, hydrophobic polyvinyl alcohol that offers excellent water resistance and gas barrier properties under high humidity conditions. The lower air permeability of coated paper provides a higher barrier to oils and greases than fully water-soluble polyvinyl alcohol, a property further enhanced when used with flake minerals. Exceval is now FDA-registered as safe for contact with food, opening doors for its use in food packaging paper.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com